1. Field of the Invention
The present invention relates to sprinkler unwinding piping connecting a water supply pipe and a sprinkler head.
2. Description of the Related Art
As this type of sprinkler unwinding piping, there is sprinkler unwinding piping which includes, for example: a flexible unwinding pipe having a required length; a union-type box nut attached to a front-end part (an upstream-end part) of the unwinding pipe, the box nut connecting the unwinding pipe and a branch joint on the side of a water supply pipe (e.g., refer to Patent Documents 1 and 2); and a sprinkler-head attachment pipe connected to a back-end part (a downstream-end part) thereof (e.g., refer to Patent Document 2 described above). However, the sprinkler unwinding piping requires a special nipple designed to be screwed to the box nut.
In recent years, in order to dispense with the special nipple, sprinkler unwinding piping has become popular in which a rotary-type nipple is attached to the connection end of a flexible unwinding pipe (a flexible pipe) on the side of a water supply pipe (e.g., refer to Patent Documents 3 and 4).
Patent Document 1 is Japanese Patent Application Laid-Open No. 6-235484, Patent Document 2 is Japanese Patent Application Laid-Open No. 7-213640, Patent Document 3 is Japanese Patent Application Laid-Open No. 2005-279200 and Patent Document 4 is Japanese Patent Application Laid-Open No. 9-294822.
However, in the sprinkler unwinding piping provided with the rotary-type nipple, a metallic sleeve member (Patent Document 3) or a resinous sleeve member (Patent Document 4) is integrally bonded in welding or resinous integral molding to the connection end of the unwinding pipe on the side of the water supply pipe, and onto the external-circumference part of the sleeve member, the rotary-type nipple is externally fitted via a seal ring and a non-slip ring. This structure is employed, and hence, the sleeve member and the non-slip ring are required to increase the number of members and the man-hours taken for the assembly thereof.